1. Field of the Invention
The present invention relates to plugs for the sealing of holes, in particular loosely toleranced holes, such as the perforations produced through the wall(s) of oilfield hole casings to sample reservoir fluid and to measure formation pressures.
2. The Prior Art
It is common, in oilfields, for the hole casings to be perforated, through the side of the casing, for purposes of sampling the fluid in the oilfield reservoir, and for determining the pressure in the oilfield formation. Once the sample has been taken, in order to restore the casing to utility for drilling or pumping purposes, the perforations must be closed. While efforts may be made to produce uniform perforations, so that they may be more easily closed, typically, the perforation will have a non-uniform circumferential contour, or the circumferential edge of the perforation may otherwise be rough.
Prior art apparatus for plugging such perforations are illustrated in Roe, U.S. Pat. No. 2,262,117; Mott, U.S. Pat. No. 4,007,905; Payton, U.S. Pat. No. 4,424,865; Geeting, U.S. Pat. No. 4,942,923; and Dave, U.S. Pat. No. 5,195,588.
It would be desirable to provide an apparatus and method for plugging such hole casings which would be capable of accommodating non-uniform or roughened perforations.